sherman943

Wasn't sure where to post due to the vast amount of problems that may or may not be connected to one another. Here's the rundown.
Have a 1991 K1500 5.7
In November I had to have a complete engine overhaul, (couldn't keep oil in it and nothing seemed to work.) And I had it done by a good trustworthy mechanic. Dealt with him for a long time. Anyway, I am still having problems and I am stumped. It seems to ocassionaly have rough idle problems. Tach will bounce up and down. Seems to be powerless. On the highway I can literally put the pedal on the floor and it won't get passed 3000 rpm's. Now I get this code 32 (EGR system) that won't go away even after I have replaced the EGR valve, EGR vacuum solenoid, and both the vacuum hoses. Doesn't have a vacuum leak that I can find. What else is there to check.
Replaced parts thus far:
Overhauled engine
Fuel Filter
Plugs, Wires, Cap, Rotor
Water pump, thermostat
Egr valve, vacuum solenoid
Battery
PCV valve and vacuum line
Muffler and exhaust
Front End (nothing to do with this problem I know)
Why won't this code go away and what the hell else could be causing this. As I mentioned I don't for sure know if all the problems are being caused by one or multiple things. Thanks

jesse06

a $50 that's potentially the problem, the Air Idle Controller its got a 4 prong plug going to it. it sits right on top of where the EGR is.

Besides stopping the truck exactly when it starts to happen and analyzing the truck for voltage, gas pressure, vacuum, your shooting in the dark by replacing parts.

but you dont mention replacing that part so I'll put my bet on that part.

the overhaul, did that change the head gaskets?

can you remove the catalytic converter to see if its all plugged up with krud?

tinbender59

there were a few of the TB motors that had an issue with the manifolds warping or cracking if I remember right, try an after market alum' manifold, cheap off of Criagslist, then have a machine shop mill a 2 inch block out to adapt the TBI onto it. I did that to my 89 shorty step side on top of a 327, made a heck of a machine, it would spank a vortec. I do a lot of off the wall sh....stuff

sherman943

sorry i forgot to mention the IAC has been replaced. Had to put a new battery in and since then it and the alternator have been checked 3 times. Says good voltage.
Head gaskets were changed in overhaul. The catalytic converter raises a good point. I suppose there is no real way to check that besides cutting it off.

Allan In NE

I think you have two problems going on here.

First the power thing: Drop the exhaust down at the donuts and take 'er for out for a drive to see if that cat is plugged up. Just plain sounds like it is.

Secondly, that code 32. "IF" you've got good vacuum to that solenoid, it's either a bad new solenoid, the wrong solenoid, or 'very rarely', a converter solenoid can set this code.

Clear all the codes. On the left side of the transmission, there is a two wire plug. Unhook this thing to disarm the converter and see if that code 32 evaporates.

Allan

jesse06

I pulled almost all the vacuum lines off of my 88 pickup and tossed the fuel pressure canister away. The only hose I can think of off hand that is hooked up is from the PCV to the carb.

mt26915

will removing my cat on my 94 1500 5.7l mess the engine up

sherman943

it shouldn't, haven't had one on mine for a long time and it hasn't caused any problems yet.

dkussard

hello, sorry for posting on an old thread..

Im running into some issues with my 91 silverado 5.7l

i just picked this truck up on the 31st with bad headgaskets. i removed the heads and replaced the gaskets with a head gasket set. i have the motor put back together and i also replaced the distributor and ignition coil. i retimed the motor and dropped the distributor in and started trying to fire the truck up. after blowing the ignition control module in the new distributor after 3 fire ups i replaced it with a brand new one again. now i get the truck runnning but it seems like its not firing on all 8.. i did a compression test and all the cylinders minus 1 tested out at 180psi. the other one tested at 140. which that being said the motor had compression in the 8 cylinders. im also getting fuel and spark on all 8. ive triple checked everything on that truck to ensure i have everything plugged in properly and every. but the truck still wont stay running unless i have my foot on the gas. has anyone else ran into an issue with this?? if so what am i missing because this is driving me insane...

burnhedge

Was the the timing advance unplugged when you set the timing?